Apparatus for aerating an aqueous solution

ABSTRACT

An aqueous stream is pumped through a vortex cylinder. The aqueous stream is rotated in a downwardly moving spiral stream within the vortex cylinder at a high downward velocity. The downward velocity of the aqueous stream increases as it flows through a discharge conduit concentrically located within a mixing chamber of the vortex cylinder. An adjustable inlet tube open to atmospheric pressure extends through the vortex chamber and into the discharge conduit. A negative pressure zone is created at the discharge end of the discharge conduit for drawing fluid into the aqueous stream for mixing therewith and dissolving oxygen in the aqueous solution.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. application Ser. No.11/859,736, filed Sep. 21, 2007, now U.S. Pat. No. 8,118,283, whichapplication is incorporated herein in its entirety by reference.

BACKGROUND OF THE INVENTION

This invention relates to a system for aerating an aqueous solution,particularly to a system for supersaturating an aqueous solution withoxygen.

Oxygen transfer within an aqueous solution is a process having utilityin a variety of industries, particularly the waste management industry.The waste management industry has found that oxygen induced intoeffluent greatly encourages growth of aerobic bacteria. Growth ofaerobic bacteria is one of two basic processes employed in the treatmentof sanitary sewerage. Aerobic bacteria is most desired in that it isactive, thereby reducing the time of processing waste materials, and itproduces a high quality effluent that can be introduced into navigablewaters, streams, lakes or disbursed on to land.

Although aerobic bacteria are efficient and effective, there are anumber of factors that must be considered when designing a wastemanagement process which will utilize aerobic bacteria. A primary factoris the cost of mechanical equipment for nurturing the growth of aerobicbacteria and assisting its positive influence. Another factor is thedestruction of aerobic bacteria by foreign material present in theeffluent. In some instances, aerobic bacteria microbes greatly diminishor cease activity due to lack of sufficient levels of oxygen in theeffluent.

A number of aeration devices have been used to aid aerobic wastemanagement systems. For example, floating mixers, spray ponds and airlifts have all been used in aerobic digestion. A commonly employedsystem utilizes an air compressor to induce large volumes of air intothe system. While this technique has encountered some success, it hasthe disadvantage of being unable to sufficiently oxygenate the effluentto permit efficient utilization of oxygen by the aerobic bacteria.

It is therefore an object of the present invention to provide a systemfor the treatment of liquid waste by intimately mixing the liquid wastewith air so that oxygen is dissolved therein, thereby providing adesirable environment for aerobic bacteria activity and oxidation of theliquid waste.

It is another object of the invention to provide a system for dissolvingoxygen in an aqueous solution by creating a low pressure vortex in theaqueous stream for drawing air into the aqueous solution tosupersaturate it with oxygen.

It is yet another object of the invention to provide a system forcreating optimal negative pressure in a vortex chamber for pumping largevolumes of air into an aqueous solution stream passing through thevortex chamber.

It is a further object of the invention to provide a process andapparatus for oxygenating an aqueous solution which is comparativelysimple in design, relatively inexpensive to manufacture and highlyeffective in performance.

SUMMARY OF THE INVENTION

In a system and process for aerating an aqueous solution, an aqueousstream is pumped through a vortex cylinder. The aqueous stream is pumpedin a downwardly moving spiral stream within a vortex chamber of thevortex cylinder at a high downward velocity. The downward velocity ofthe aqueous stream increases as it flows through a discharge conduitconcentrically located within a mixing chamber of the vortex cylinder.An adjustable air inlet tube open to atmospheric pressure may extendthrough the vortex chamber and into the discharge conduit. A negativepressure zone created at the discharge end of the discharge conduit anda lower portion of the mixing chamber draws air into the aqueous streamfor mixing therewith and dissolving oxygen in the aqueous solution. Theprocess may include a secondary air or aqueous stream inlet forincreasing the volume of air or aqueous solution drawn into the negativepressure zone.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features, advantages andobjects of the present invention are attained can be understood indetail, a more particular description of the invention brieflysummarized above, may be had by reference to the embodiments thereofwhich are illustrated in the appended drawings.

It is noted, however, that the appended drawings illustrate only typicalembodiments of this invention and are therefore not to be consideredlimiting of its scope, for the invention may admit to other equallyeffective embodiments.

FIG. 1 is an elevation view, partially in section and partially brokenaway, of a first embodiment of a system for aerating an aqueous stream;

FIG. 2 is a section view taken along line 2-2 of FIG. 1;

FIG. 3 is a side view of a valve assembly of the system shown in FIG. 1;

FIG. 4 is an elevation view, partially in section and partially brokenaway, of a second embodiment of a system for aerating an aqueous stream;and

FIG. 5 is an elevation view, partially in section and partially brokenaway, of a third embodiment of a system for aerating an aqueous stream.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Referring first to FIG. 1, a system for aerating an aqueous solution orstream is generally identified by the reference numeral 10. As shown inFIG. 1, the system 10 comprises a vortex cylinder 12 and a pump 14. Thepump 14 is connected to the vortex cylinder 12 by a pipe conduit 16. Agauge 18 is located between the pump 14 and the vortex cylinder 12 tomonitor the pressure of the aqueous solution as it is pumped to thevortex cylinder 12.

A suction hose 20 is connected to the inlet end of the pump 14. Thesuction hose 20 is of sufficient length to reach the bottom of a tank,lagoon or collection pond 22. The inlet end 24 of the suction hose 20may be capped with a screen or the like to screen out solid debris suchas rocks, wood, twigs or the like which may clog the pump 14.

A discharge hose 26 is connected to a discharge port or opening 28 ofthe vortex cylinder 12. The discharge hose 26 discharges the aeratedaqueous solution at the bottom of the pond 22. Thus, excess or freeoxygen in the discharged aerated aqueous solution percolates upwardlythrough the aqueous solution in the pond 22 so that the dissolved oxygenlevel throughout the pond 22 is elevated to the saturation pointrelatively quickly.

Referring still to FIG. 1, the vortex cylinder 12 comprises an uppercylinder chamber 38 and a lower cylindrical chamber 44. The upperchamber 38 is closed at the top end thereof by an upper wall 36. Thelower chamber 44 is closed by a bottom wall 42. The upper chamber 38 ofthe vortex cylinder 12 is separated from the lower chamber 44 by aninwardly sloping circumferential wall 46 defining the lower end of theupper chamber 38. The wall 46 circumscribes an opening 48 providingaccess between the upper chamber 38 and the lower chamber 44. An axiallydisposed discharge conduit 50 depends downwardly from the bottom wall 46into the lower cylindrical chamber 44. The discharge conduit 50 isconcentrically disposed within the lower chamber 44 and terminates at anend 52 at a point above the bottom 42 of the lower chamber 44 of thevortex cylinder 12. The upper end of the discharge conduit 50circumscribes the opening 48 in the wall 46.

The upper wall 36 of the upper cylindrical chamber 38 is provided withan opening providing access to the upper chamber 38. A valve assembly 56is mounted on the upper wall 36 of the vortex cylinder 12 and includes aportion thereof extending upwardly above the vortex cylinder 12. Thevalve assembly 56 includes an air intake tube 51 that extends into thevortex cylinder 12 when the valve assembly is assembled and secured tothe upper wall 36 of the vortex cylinder 12. The air intake tube 51 isconcentrically located within the upper chamber 38 of the vortexcylinder 12 and the lower portion thereof extends through the opening 48in the bottom wall 46 of the upper chamber 38 into the discharge conduit50. The air intake tube 51 is concentrically positioned within thedischarge conduit 50 and terminates at a point above the end 52 of thedischarge conduit 50. The air intake tube 51 may be adjusted up or downto locate the optimal position for maximizing the negative pressure zonedeveloped in the lower end of the discharge conduit 50.

Referring now to FIG. 3, the upstanding air valve assembly 56 is shownin greater detail. The valve assembly 56 includes valve componentsconnected end to end stacked one above the other and includes an axialpassageway extending therethrough. The air intake tube 51 is the bottomor lower member of the valve assembly 56. The upper end of the airintake tube 51 terminates in an externally threaded coupling 70. The airintake tube 51 includes an externally threaded portion 72 below thecoupling 70 for threaded engagement with a mounting collar 54 or thelike. The collar 54 is open at both ends thereof and may be welded orotherwise fixed on the vortex cylinder 12. The valve assembly 56 ismounted on the vortex cylinder 12 by inserting the lower portion of theair intake tube 51 through the collar 54 to the threaded portion 72 ofthe air intake tube 51 and threadably securing the valve assembly 56 onthe vortex cylinder 12.

A tee connector 80 is connected to the coupling 70 in axial alignmenttherewith. The tee 80 includes a gauge 82 mounted thereon. The gauge 82measures the pressure developed in the negative pressure zone below thelower end 52 of the discharge conduit 50. A ball valve 90 mounted abovethe tee 80 automatically closes the air intake passageway of the valveassembly 56 in the event fluid is forced up the air intake tube 51. Acheck valve 92 mounted above the ball valve 90 permits adjustment of theair flow through the passageway of the valve assembly 56. An air filter100 mounted above the check valve 92 completes the valve assembly 56.The air filter 100 prevents large particles and debris from entering theair intake passageway of the valve assembly 56.

In the operation of the system 10, the pump 14 pumps an aqueous solutioninto the upper end of the upper cylindrical chamber 38 through the inletconduit 16. The inlet conduit 16 is provided with a nozzle 58 whichterminates in a nozzle opening 60 which is offset from the longitudinalaxis of the vortex cylinder 12, as best shown in FIG. 2. The aqueoussolution is injected into the upper chamber 38 of the vortex cylinder 12at a high velocity. The high velocity aqueous stream impinges on thecylindrical wall 34 and produces a swirling vortex descending downwardlyin the upper chamber 38 as noted by the arrows 62. The swirling vortexhas a constant radius in the cylindrical chamber 38, which radius inlimited by the radius of the chamber 38. As the swirling stream extendsdownward into the upper cylindrical chamber 38, it is forced through theopening 48 in the bottom wall 46 into the discharge conduit 50. Theinternal diameter of the conduit 50 is less than the internal diameterof the upper cylindrical chamber 38. The swirling aqueous stream istherefore compacted and the velocity of the aqueous stream increases sothat a negative pressure zone is created at the point 62 within thedischarge conduit 50, just below the end 64 of the air intake tube 51.As the aqueous solution stream descends in a vortex in the dischargeconduit 50, centrifugal forces acting on the solution stream increasethe velocity of the aqueous solution and create the negative pressurezone 62. The pressure drop in the low pressure zone 62 may reach thirtyinches of mercury (Hg), creating a substantial pressure drop across theend 64 of the air intake tube 51. At the pressure differential developedby the system 10, air velocity exiting the air intake tube 51 is in therange of 700 to 1,000 feet per second generating a volume of 30 to 60feet per minute of air aspirated into the aqueous solution dischargedthrough the discharge conduit 50. The pressure differential may bemaximized by advancing the air intake tube 51 up or down to locate theoptimal distance between the lower end 64 of the air intake tube 51 andthe lower end 52 of the discharge conduit 50. The air intake tube 51 ismoved up or down by grasping the handle 102 and rotating the valveassembly 56 clockwise or counter clockwise. For example, one turn of thevalve assembly 56 may translate to a three inch vertical movement of theair intake tube 51. Air intake may also be controlled by manipulatingthe check valve 92 to limit the air volume flowing through the airpassageway of the valve assembly 56. The air and aqueous solution aremixed in the lower cylindrical chamber 44 and the oxygen rich aqueoussolution is discharged through the discharge hose 26 into the collectionpond 22.

Referring now to FIG. 4, a second embodiment of a system for aerating anaqueous solution or stream is generally identified by the referencenumeral 200. The system 200 is substantially similar to the system 10described above with the exception that the lower end 42 of the mixingchamber 44 of the vortex cylinder 12 is open. An inlet opening or port210 may be provided proximate the upper end of the mixing chamber 44.The port 210 is open to the atmosphere. Air may be aspirated through theport 210 into the mixing chamber 44. In this manner, air may beintroduced into the mixing chamber 44 through the air intake tube 51 andthe port 210 thereby increasing the volume of oxygen available formixing with the aqueous solution. Vigorous mixing of air and aqueoussolution maximizes the sub-micro size oxygen molecules that remain insolution for aerobic bacteria activity and oxidation of the aqueoussolution.

Referring now to FIG. 5, the system 200 for aerating an aqueous solutionis depicted positioned so that the port 210 opening into the mixingchamber 44 is submerged below the water surface. Aspirating aqueoussolution through the port 210 increases the volume of aqueous solutionin the mixing chamber 44 resulting in greater agitation of the air/fluidmixture in the negative pressure zone 62 to maximize the sub-micro sizeoxygen molecules that remain in solution for aerobic bacteria activityand oxidation of the aqueous solution.

It will be understood that certain combinations and sub-combinations ofthe invention are of utility and may be employed without reference toother features in sub-combinations. This is contemplated by and iswithin the scope of the present invention. As many possible embodimentsmay be made of this invention without departing from the spirit andscope thereof. It is to be understood that all matters hereinabove setforth or shown in the accompanying drawings are to be interpreted asillustrative and not in a limiting sense.

While a preferred embodiment of the invention has been shown anddescribed, other and further embodiments of the invention may be devisedwithout departing from the basic scope thereof, and the scope thereof isdetermined by the claims which follow.

The invention claimed is:
 1. An apparatus for aerating an aqueoussolution, comprising: a) a vortex cylinder operatively connected to apump, said vortex cylinder including a vortex chamber and a mixingchamber, wherein said mixing chamber includes an open lower end; b) atransverse wall separating said vortex chamber from said mixing chamber,said transverse wall including a centrally located opening providingfluid communication between said vortex chamber and said mixing chamber;c) a discharge conduit concentrically disposed within said mixingchamber, wherein said discharge conduit extends downwardly from saidwall and includes an upper end circumscribing said opening; d) an airintake tube concentrically disposed within said vortex cylinder, saidair intake tube including an upper portion extending through a top wallof said vortex cylinder, said upper portion of said air intake tubeincluding an externally threaded section engaging a threaded collarmounted on said top wall of said vortex cylinder, and wherein a lowerportion of said air intake tube extends into said discharge conduit andterminates at a point spaced above a lower end of said dischargeconduit; e) a valve assembly having an axially extending air intakepassageway connected to said air intake tube; and f) an inlet portproximate an upper end of said mixing chamber, said inlet port providingfluid access to said mixing chamber.
 2. The apparatus of claim 1 whereinsaid valve assembly comprises: i. a pressure gauge in fluidcommunication with said air intake passageway; ii. a first valve forautomatically closing said air intake passageway of said valve assembly;iii. a second valve for adjusting air flow through said air intakepassageway, iv. an air filter for filtering air entering said air intakepassageway; and v. means for vertically adjusting said air intake tubeto maximize the pressure differential developed proximate said lower endof said discharge conduit.
 3. The apparatus of claim 1 wherein saidvalve assembly includes a check valve.
 4. The apparatus of claim 3further including an air filter mounted above said check valve.